Buy from a metal building supplier who will give you engineered stamp prints.  

Give Home Depot a shot.Alternatively, see if you can find a pre-bullnosed granite slab supplier within driving distance.

Many builders "and SMART investors" form "Builder/Investor Buying Groups" where they share subcontractors and suppliers to increase their collective purchasing power and CLOUT when it comes to having their jobs done when they want them.If I just had one kitchen sink to replace, the plumber may "get to me when he can", but if my team and I can keep a few of his crews busy month after month after month, I can pretty much count on him replacing that sink for me anytime I need it.And Remember, Economies of Scale applies not only to purchasing power, but KNOWLEDGE too!  

Be sure to lapse the 20 day notice, in case of suppliers and subs.Anyway, here is the provision where you could stand ground. 

TV and telecommunication service is one sector that's experiencing negative inflation LOLmeaning the supplier is selling below their production cost, sometimes TV and cell phone cost is much less than a nice BBQ dinner outside LOL

@Lenny Markus you can pay for flooring supplies directly from the supplier and set up delivery to the property if they want money upfront for supplies. 

Soon I realized that when you are rehabbing an old house you will find with doors with odd sizes which you can't find in HD, and the only option is going custom or working with a local door supplier that might have doors to that size.This is the living room, the walls had different textures all over the place.

I either pick up the materials or have the supplier delivery. 

Do you also have a list of subcontractors, vendors (material suppliers) and architects and designers that have partnered with you that I can call?

If I’m doing per line then I ask for material money upfront so I don’t get burned and I can pay off my suppliers.